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XB misfire at constant RPM cruising (~3500 RPM).

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Well after a new fuel pump, new injectors, a $240 trip to a mechanic who "fully seated 1 fuel injector" and then the extra ground I unfortunately have to say it still runs like **** at about 3500 rpms. What's next, i don't know but I am open to suggestions. I can reset the the TPMS and it might run better for another 2 or 3 rides but then it will be back. It's sad because I really like riding this bike when it runs right which is not as often as it should be.
 
Well after a new fuel pump, new injectors, a $240 trip to a mechanic who "fully seated 1 fuel injector" and then the extra ground I unfortunately have to say it still runs like **** at about 3500 rpms. What's next, i don't know but I am open to suggestions. I can reset the the TPMS and it might run better for another 2 or 3 rides but then it will be back. It's sad because I really like riding this bike when it runs right which is not as often as it should be.

I'm sure you did already but did you clean the IAC and the throttle body? And I mean CLEAN. Take off the velocity stack, twist the throttle and open the butterfly valve and get yourself some throttle body cleaner, spray it on a long, soft flexible brush and do a proper cleaning.
 
chickn and Nick900,

I agree wholeheartedly how some of the threads get WAY off track. I attempted to use satire as a tool to help diminish this trend, as well as try some humor to lighten the whole conversation. You might review your comments in light of that.

Opto
 
Note: xb12Ss with 35,000 miles. So original seals were well used.

Darin: Sorry to hear that. What you did matches my work. Yours actually looks a little cleaner.

I do not know what sensors are matched with ground A and which are ground B (see diagram I attached earlier). Or if ground A and B are connected. Perhaps your issue is with the "A" ground. But before hacking into the harness again, you can test. Before I hacked my harness, I stuck a very fine sewing needle into the terminal from the top side and made a temporary ground from the needle using alligator clips. I had to use wire cutters to get the right needle length (sticks out of terminal but is cleared by the seat). It was not 100% but the bike ran better - enough that I figured it was worth trying the extra ground. I put a drop of rubber cement on the hole when done.

In all of my research, i did learn two interesting things that might be affecting you:
1) The seals on the intake (throttle body) are known to fail and allow air to slip in. When my throttle body was pulled (replace the entire throttle body), the streaks on the head were visible where air was being sucked in. This would cause a lean condition. One of my hypothesis was that I had a vibration related air leak causing a lean condition and then the computer freaking out. Obviously, there was a ground issue but I cannot rule out the possibility that I also had an air seal issue.
2) Apparently, the coils can fail intermittently. You noted new plugs and injectors. Coil is easy to change and not terribly expensive.

Also:
3) TPS sensors can develop dead spots (all tps sensors, not just buell). In 24 years, I have replaced 3 TPS sensors on my firebird. A TPS in general should read 0.5 to 5 V from off to WOT. And it should be a linear with throttle. In the case of my Firebird, the sensors would fail in the just off idle range where you tend to have the throttle when cruising (i.e. largest percentage of time). Try measuring the output voltage and look for a dead spot. Go REALLY slowly and look for places where the output fluctuates faster than your hand.

I hope this helps...

Note: xb12Ss with 35,000 miles. So original seals were well used.
 
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Plugged in the ECM spy and snapped a couple screen shots as this bike is new to me along with the ECM spy software the only thing I know how to do with the software besides seeing what is going on is reset the TPS. I don't know how much this matters but the previous owner sent out the factory muffler to someone who modified it.

Buell1.jpg

Buell2.jpg
 
I added an extra wire to give better ground to ECU but surprice surprice, no significant change. Still stutters, and backfires. Maybe little better when hot, but...

Next I clean the throttle body.

Previous owner did mess with the original ECU program and put in Twin Motorcycles software for open air box and Jardine muffler. K&N filter is still on but with the original muffler. I bought a Buell-tooth and I have to study it before I mess up my bike so bad that it would not even start.
 
I was amazed at how much better my bike ran after I cleaned out the throttle body.

I used a long wire bottle brush sprayed with TB cleaner to loosen the tough soot. I trimmed down the bristles with a scissor till I liked the length. Then I took a small piece of microfiber cloth sprayed in TB cleaner, wrapped it around the tip of the brush and secured it with a zip tie, so as not to lose it in the throttle body. I removed a substantial amount of soot. Then I cleaned the IAC with carb cleaner sprayed onto a microfiber cloth. The tip of the IAC was coated in soot.

The bike came alive after the cleaning. It was like it got a whole new set of lungs.

You have to remove the velocity stack and zip tie the throttle tube to the brake lever to keep the butterfly valve open while you do the job.
 
Plugged in the ECM spy and snapped a couple screen shots as this bike is new to me along with the ECM spy software the only thing I know how to do with the software besides seeing what is going on is reset the TPS. I don't know how much this matters but the previous owner sent out the factory muffler to someone who modified it.

View attachment 10299

View attachment 10300

in all likelihood either a faulty ecm or your TPS unit going bad. link below and go to 2.2 section and beyond. shows simple voltage test for TPS unit done with multi-meter. another simple TPS test is by checking its ohms with multi-meter. i tested a new 2007 TPS unit years ago and supplied the ohms readings on here for board members. simple test anyone can do and well worth the effort prior to replacing it. your symptoms point to the above. here's the test in OHMS:
BUTTERFLY FULLY CLOSED IS APPROX. 560 OHMS-----BUTTERFLY FULLY OPENED INCREASES INCREMENTLY TO 3.82 KOHMS.

and here ya go...
http://www.ukbeg.com/pash/2008 Buell XB/99493-08Y.pdf
 
I cleaned the throttle body and then it started running so bad it was back firing into the airbox. I put a new TPS in and the manual said it needed to be calibrated with a HD part number tool, so I dropped it off at the only Harley dealer near me that still works on Buels. A week later they call back and say engine temp sensor is bad and they can't set TPS without it working right. So a new temp sensor, a new calibrated TPS, and it now runs like it should.

Only thing now is they said they can't turn off the check engine light because of my modified factory muffler so it's on all the time. The fan runs a lot more than it did before the new sensor I am assuming it now runs as it should and was not running enough in the past.
 
Hello everybody!

New season is about to start here in Finland. Only -5°C / 23°F in the morning.

Now I have a new set of O-rings at intake manifold and this time I got the rubber intake nozzle right too. Installed a new program (K&N+Jardine) to ECU and calibrated the TPS. Still the bike isn't perfect but it runs better than it did last summer. No backfire, and idle is steady. Now I have a tank full of E98 gasoline with RedLine injector cleaner in it. Lets see if it helps.
 
You can easily turn off the CEL if the aftermarket muffler is causing it. That way you will know if theres other issues making it turn on. Check what code you have BEFORE you clear it. I think 21 is for the IEV, IIRC.

ECMDroid is the easiest. Go to ECM parameters/scroll to the bottom and uncheck IEV. ECMspy will do it too if you are better versed wit that program.
 
I took a short 25miles test-drive and she was promising. I have K&N filter with original muffler. Previous owner did have a Jardine muffler on it. I would like to have it back.
 
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Hi

I have this misfire at 2500 rpm cruising. Give it a bit of gas, it runs smoothly. Bike (XB12S '06) has been standing about two years and now been started up again by me. I filled gas tank with a fresh fuel and added some RedLine SI-1. Bike feels a bit smoother but stutter at high rpm but doesn't misfire. Tomorrow i have to check every connection and maybe polish some connection points to ground.

(and sorry about my english)

wwwili

I have the same problem with my 07Ulysses. It sat for two years before I bought it. 2400 to 3000 rpm it stutters, but no all the time. Sometime is goes a week without a problem, then it is nothing but stutters. I find the problem when cruising around town. At highway speeds there is no issues. How'd yours turn out?
 
Well after a new fuel pump, new injectors, a $240 trip to a mechanic who "fully seated 1 fuel injector" and then the extra ground I unfortunately have to say it still runs like **** at about 3500 rpms. What's next, i don't know but I am open to suggestions. I can reset the the TPMS and it might run better for another 2 or 3 rides but then it will be back. It's sad because I really like riding this bike when it runs right which is not as often as it should be.

I feel exactly the same way. I have owned 15 bikes and this Ulysses suits me better than any I have owned. I have never rode a bike that fit me better in handling and comfort. Some days it has no stumble, some days it stumbles so bad I park it. I had a 2010 Lightning and it had way more power than my 07 ulysses and it had no stumble issues. Man, I wish I hadn't sold that bike.
 
The tach on my 2004 XB12S is behaving erratically. I have checked electrical connections including fuses and relays, done the earth ground cleaning, cleaned all electrical connections, and added the extra ground from the ECM to the battery. The tachometer output when logging is fine (i.e., does not show the what the tach is showing) so it seems to be electrical. I saw this thread and thought I would take a look at the ground at the forks, which is not shown in my owners manual, to see if that could be the problem. The bolt behind the headlights and the bolts behind the forks are there but there are not ground wires running to either of them. I have owned her since 2011. Do the 2004's not have this grounding point? Could previous owner have removed them? Should I add ground here and if so where do the ground wires originate from?

I have read, asked, and tried everything I can think of and find to fix the tach issue and was hoping that this was it. When it started, I had not done anything new to the bike that would point to an issue.
 
If your dash ground was compromised the speedo/ lights wouldn't work either.

So either you have a bad signal wire from the ECM to the dash, or you have an issue in the cluster. Check the tach signal at the harness plug of the dash to determine which one.
 
Hey Cooter, how do I check the tach signal at the plug or what am I looking for. I know that there is a table in the electrical guide that shows the voltages that should correlate to speed but I have yet to find anything similar for the tach.
 
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